56 lines · cpp
1//===-- VASprintf.cpp -----------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "lldb/Utility/VASPrintf.h"10 11#include "llvm/ADT/SmallString.h"12#include "llvm/ADT/SmallVector.h"13#include "llvm/ADT/StringRef.h"14 15#include <cassert>16#include <cstdarg>17#include <cstdio>18 19bool lldb_private::VASprintf(llvm::SmallVectorImpl<char> &buf, const char *fmt,20 va_list args) {21 llvm::SmallString<16> error("<Encoding error>");22 bool result = true;23 24 // Copy in case our first call to vsnprintf doesn't fit into our buffer25 va_list copy_args;26 va_copy(copy_args, args);27 28 buf.resize(buf.capacity());29 // Write up to `capacity` bytes, ignoring the current size.30 int length = ::vsnprintf(buf.data(), buf.size(), fmt, args);31 if (length < 0) {32 buf = error;33 result = false;34 goto finish;35 }36 37 if (size_t(length) >= buf.size()) {38 // The error formatted string didn't fit into our buffer, resize it to the39 // exact needed size, and retry40 buf.resize(length + 1);41 length = ::vsnprintf(buf.data(), buf.size(), fmt, copy_args);42 if (length < 0) {43 buf = error;44 result = false;45 goto finish;46 }47 assert(size_t(length) < buf.size());48 }49 buf.resize(length);50 51finish:52 va_end(args);53 va_end(copy_args);54 return result;55}56